Multicomponent force measuring by means of dynamometers and with flat washer sensors is familiar. For such applications piezoelectric metrology employing quartz load washers for compressive and shear loading has gained acceptance. The quartz crystal disks used for this are all cut longitudinally from the quartz rods. Piezoelectric ceramics might be used in principle, though they have not found acceptance because static calibration is necessary.
Also known in piezoelectric pressure transducers are piezoelectric crystals as rod elements cut transversely.
The invention is based on the new discovery that such piezoelectric rod elements may be employed for forming flexural moment, making possible multicomponent force measurement provided their signals are processed appropriately. Such force and moment transducers can be made very compact and simple. They are suitable for miniaturization, because the signal strength is many times greater than that with disk crystal arrays.
A measuring arrangement according to the invention is characterized by at least two piezoelectric elements sensitive to compression and tension respectively, with a common force introducing element, being disposed so that they measure both pressure and tension components, and also add or subtract as the case may be compressive or tensile forces set up in pairs by moment forces, resulting in the piezoelectric elements from one or more moments acting on the measuring arrangement, whereby the addends are led as signal charges to evaluation circuitry.
The invention and other features and advantages associated with it are explained in more detail below, with reference to the typical embodiments illustrated in the drawing.